Certain types of test equipment, such as logic analyzers and timing analyzers, have a large number of input data channels. The usual situation is for a number of channels to be grouped together as components of some measurable abstraction (such as addresses or data that are part of transactions on a bus). Each channel has an associated probe, and a result of such operation is a requirement that there be a known probe to signal correspondence, which is usually declared during set-up or configuration. There are other times, however, when a channel and its probe can be used as part of a measurement made in some mode not involving correspondence among multiple probes or channels. Say, for example, the test equipment were a logic analyzer, and some difficulty was being experienced in trying to set up and perform some measurements involving multiple channels. Someone suggests that perhaps a clock signal, or maybe some other necessary signal, is absent or abnormal. One could go get an oscilloscope and set it up to find out, or, as an example use of the invention, one could instead grab any probe (unused or otherwise), touch it to a particular (special) terminal on the front panel to invoke a single channel waveform display whose input is that channel, and then display the waveform for the signal of interest by moving the probe to a place where that signal is present. The single channel display mode of operation for that channel would remain in effect until cancelled by some affirmative action, such as an appropriate series of keystrokes on a keyboard, clicking a mouse button while a pointer is over a displayed legend, or perhaps by simply moving the probe tip to again touch the special terminal. The nature of the special mode (time domain waveform display versus, say, measurement of RMS value) may be fixed ahead of time or specified (say, in a menu) upon leaving the "normal" mode. Other special modes of operation include performance verification and a stimulus mode. The desired special mode of operation could also be specified by which of several corresponding terminals were touched by the probe. If any such terminal were touched with two probes, then each of the two corresponding channels would enter a special mode, and there may be a choice of whether to treat them as separate single channel measurements (which are possibly not of the same nature) or as one two channel measurement. In any event, considerable utility arises from being able to make a measurement in some special mode using whatever probe happens to be handy, and without having to know ahead of time what channel that probe corresponds to.